Infiltration basin

An infiltration basin, is a type of best management practice (BMP) that is used to manage stormwater runoff, prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake or bay. It is essentially a shallow artificial pond that is designed to infiltrate stormwater though permeable soils into the groundwater aquifer. Infiltration basins do not discharge to a surface water body under most storm conditions, but are designed with overflow structures (pipes, weirs, etc.) that operate during flood conditions. [New Jersey Department of Environmental Protection. Trenton, NJ. [http://www.njstormwater.org/tier_A/pdf/NJ_SWBMP_9.5.pdf "New Jersey Stormwater Best Management Practices Manual."] Chapter 9.5: Standard for Infiltration Basins. April 2004.] [U.S. Environmental Protection Agency. Washington, D.C. [http://epa.gov/guide/stormwater/ "Preliminary Data Summary of Urban Storm Water Best Management Practices."] Chapter 5. August 1999. Document No. EPA-821-R-99-012.]

It is distinguished from a detention basin, sometimes called a dry pond, which is designed to discharge to a downstream water body (although it may incidentally infiltrate some of its volume to groundwater); and from a retention basin, which is designed to include a permanent pool of water.

Design Considerations

Infiltration basins must be carefully designed to infiltrate the soil on a given site, at a rate that will not cause flooding. They have been less effective in areas with:
*high groundwater levels, close to the infiltrating surface;
*compacted soils;
*high levels of sediment in stormwater; or
*high clay soil content. [ [http://wef.org Water Environment Federation,] Alexandria, VA; and [http://www.asce.org American Society of Civil Engineers,] Reston, VA. [http://books.google.com/books?id=AdU-VXXV_H0C "Urban Runoff Quality Management."] WEF Manual of Practice No. 23; ASCE Manual and Report on Engineering Practice No. 87. 1998. ISBN 1-57278-039-8. Chapter 5.] At some sites infiltration basins have worked effectively where the installation also includes an extended detention basin as a pretreatment stage, to remove sediment. [U.S. EPA. [http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=browse&Rbutton=detail&bmp=69 "National Menu of Stormwater Best Management Practices: Infiltration Basin."] ] The basins may fail where they cannot be frequently maintained, and their use is discouraged in some areas of the United States. For example, they are not recommended for use in the State of Georgia, which has many areas with high clay soil content. [Atlanta Regional Commission. Atlanta, GA. [http://www.georgiastormwater.com/vol2/3-1.pdf "Georgia Stormwater Manual: Volume 2."] Page 3.1-5. 2001.]

ee also

*Dry well
*Percolation trench
*Sustainable urban drainage systems

References

External links

* [http://www.mde.state.md.us/Programs/WaterPrograms/SedimentandStormwater/stormwater_design/index.asp Maryland Stormwater Design Manual] - See Section 3.3 for Infiltration Feasibility Criteria & Design Diagrams
* [http://bmpdatabase.org International Stormwater BMP Database] - Performance Data on Urban Stormwater Best Management Practices

*Stormwater management Tools:
** [http://www.toolkit.net.au/music Model for Urban Stormwater Improvement Conceptualisation (MUSIC)]